Floyd Mayweather may be the last person on the planet to admit doubt or concern, but that doesn't mean he shouldn't have either heading into his highly anticipated bout against Marcos Maidana.

At is 37 years old, Mayweather is 45-0 in his career and, with each passing fight, he tempts the pugilistic fates to take away his perfect record. Every Mayweather bout is charged with that potential and makes him all the more averse to forces—beyond his control, no less—that might tarnish his legacy.

In the Adrien Broner fight, Maidana was a lot stronger than in his past fights," Mayweather suggested. "I don't know if Alex Ariza played a major role. When I sit back and look at Pacquiao v Bradley, I've noticed that ever since Ariza has not been with Pacquiao, there's been a total change in his power.

Mayweather was careful not to make any specific allegations, but he is known for his commitment to clean fights and stringent drug testing: a key point of contention that has denied the world a Mayweather-Pacquiao fight.

The concern about strength is highlighted by Maidana's reputation as a vicious slugger. Maidana is 35-3, with 31 of those victories recorded via knockout. Maidana's last bout was a victory against then-undefeated Adrien Broner, a fighter of similar style and stature to Mayweather.

Maidana knocked him down twice—in the second and eighth rounds of the bout—en route to a unanimous decision and the WBA Welterweight title. The second round knockdown was a perfect example of the kind of wild punching that Maidana uses to sometimes-devastating effect (5:37 mark of the video).

A 45-0 record doesn't mean much to a well-timed haymaker, so Mayweather will have to be at the top of his unparalleled defensive game to maintain his record at his advanced age. However, not everyone is convinced Mayweather's speed and defense will matter against Maidana. Jesus Soto Karass, a boxer who has faced Maidana in the past, made this point to Tim Smith of Showtime Boxing Blog.

“Broner had the same style as Floyd, but Maidana’s punching power will play a big role in the fight. His (Mayweather’s) speed will not be able to affect it,’’ Karass said.

Mayweather is 37 years old and might not have the speed necessary to avoid Maidana, who is 30 years old and in peak physical condition. Of course Mayweather counters that particular notion, according to Sam Farmer of the Los Angeles Times.

A loss is an unlikely outcome for Mayweather, but there is always a risk and no rematch can ever bring back perfection. Mayweather is arguably the best pound-for-pound fighter of all time and the fact that this fight is taking place at the welterweight class—rather than the heavier, light-middleweight—bodes well for his natural quickness advantage. Maidana leaves himself open to counterpunches: something Mayweather will need to take full advantage of, if he wants to end this fight early.

Should Maidana upset Mayweather, he would instantly propel himself to the pinnacle of the boxing pyramid and open up access to all kinds of lucrative fights and sponsorships, while Mayweather would have to contend with losing his perfect record.